Solenoid device

Abstract

A solenoid device includes: a first electromagnetic coil; first and second plungers movable according to energization to the first electromagnetic coil; first and second fixed cores facing the first and second plungers, respectively; and a yoke. When the first electromagnetic coil is not energized, first and second gaps are formed between the first and second plungers and the first and second fixed cores, respectively. When the first electromagnetic coil is energized, the magnetic flux flows in a first magnetic circuit, provided by the first plunger, the first fixed core and the yoke, via the first gap, and a second magnetic circuit, provided by the first and second plungers, the first and second fixed cores and the yoke, via the first and second gaps, so that the first and second plungers are attracted toward the first and second fixed cores.

What is claimed is: 
     
       1. A solenoid device comprising:
 a first electromagnetic coil for generating magnetic flux when current passes through the first electromagnetic coil; 
 a first plunger and a second plunger, each of which moves backward and forward according to energization to the first electromagnetic coil; 
 a first fixed core facing the first plunger in a backward-forward movement direction of the first plunger; 
 a second fixed core facing the second plunger in a backward-forward movement direction of the second plunger; and 
 a yoke, 
 wherein the yoke, the first plunger, the first fixed core, the second plunger, and the second fixed core provide a magnetic circuit, in which the magnetic flux flows, 
 wherein, when the first electromagnetic coil is not energized in a unenergization state, a first gap is formed between the first plunger and the first fixed core, and a second gap is formed between the second plunger and the second fixed core, 
 wherein, when the first electromagnetic coil is energized in a energization state, the magnetic flux flows in a first magnetic circuit, provided by the first plunger, the first fixed core and the yoke, and a second magnetic circuit, provided by the first plunger, the first fixed core, the second plunger, the second fixed core and the yoke, 
 wherein, when the first electromagnetic coil is energized in the energization state, the first plunger is attracted toward the first fixed core by magnetic force, which is generated by a flow of the magnetic flux in the first magnetic circuit, and the second plunger is attracted toward the second fixed core by magnetic force, which is generated by a flow of the magnetic flux in the second magnetic circuit, and 
 wherein, while switching from the unenergization state to the energization state, the magnetic flux flowing in the first magnetic circuit passes through the first gap, and the magnetic flux flowing in the second magnetic circuit passes through the first gap and the second gap. 
 
     
     
       2. The solenoid device according to  claim 1 ,
 wherein the yoke includes a magnetic saturation part disposed on the first magnetic circuit, the magnetic saturation part, in which magnetic saturation locally occurs, and 
 wherein the magnetic saturation part regulates an amount of the magnetic flux flowing in the first magnetic circuit. 
 
     
     
       3. The solenoid device according to  claim 1 ,
 wherein the first electromagnetic coil has a first coil part and a second coil part, each of which is energized independently, 
 wherein the first coil part is disposed in a position closer to the first fixed core than the second coil part in the backward-forward movement direction of the first plunger, 
 wherein the yoke includes: an intermediate yoke disposed between the first coil part and the second coil part; and a sliding-contact yoke disposed in a position farther from the first fixed core than the intermediate yoke in the backward-forward movement direction of the first plunger, 
 wherein the first plunger and the second plunger slide in contact with the sliding-contact yoke, 
 wherein, when only the first coil part is energized, the first plunger is attracted toward the first fixed core by the magnetic force, which is generated by magnetic flux flowing in the intermediate yoke, the first plunger and the first fixed core, and 
 wherein, when only the second coil part is energized, the first plunger is attracted toward the sliding-contact yoke by magnetic force generated by magnetic flux flowing in the intermediate yoke, the first plunger, and the sliding-contact yoke so that the first plunger is moved apart from the first fixed core. 
 
     
     
       4. The solenoid device according to  claim 3 ,
 wherein the first plunger includes a flange having a diameter larger than a body of the first plunger in a radial direction of the first plunger, and 
 wherein, when the first electromagnetic coil is not energized in a unenergization state, a length between the flange and the sliding-contact yoke in the backward-forward movement direction of the first plunger is shorter than a length between the intermediate yoke and the flange. 
 
     
     
       5. The solenoid device according to  claim 1 ,
 wherein each of the first plunger and the second plunger has a plate shape, 
 wherein each of the first plunger and the second plunger moves backward and forward in a plate thickness direction of the plate shape, 
 wherein, when each of the first plunger and the second plunger moves backward and forward, each of the first plunger and the second plunger contacts and moves apart from a surface of the yoke. 
 
     
     
       6. The solenoid device according to  claim 5 , further comprising:
 a pillar-shaped core inserted in a center of the first electromagnetic coil, 
 wherein the first fixed core and the second fixed core are integrated into the pillar-shaped core, 
 wherein the first plunger is disposed on one side of the first electromagnetic coil in an axial direction of the pillar-shaped core, and 
 wherein the second plunger is disposed on the other side of the first electromagnetic coil in the axial direction of the pillar-shaped core. 
 
     
     
       7. The solenoid device according to  claim 5 ,
 wherein, when the first electromagnetic coil is not energized in the unenergization state, a third gap is formed between the first plunger and the yoke, and a fourth gap is formed between the second plunger and the yoke, and 
 wherein, while switching from the unenergization state to the energization state, the magnetic flux flowing in the first magnetic circuit passes through the first gap and the third gap, and the magnetic flux flowing in the second magnetic circuit passes through the first gap, the third gap, the fourth gap and the second gap. 
 
     
     
       8. The solenoid device according to  claim 1 , further comprising:
 a second electromagnetic coil for generating magnetic flux when current passes through the second electromagnetic coil; 
 a third plunger moving backward and forward according to energization to the second electromagnetic coil; and 
 a third fixed core facing the third plunger in a backward-forward movement direction of the third plunger, 
 wherein, after the first electromagnetic coil is energized in the energization state so that the first plunger is attracted toward the first fixed core, and the second plunger is attracted toward the second fixed core, the second electromagnetic coil is energized so that the third plunger is attracted toward the third fixed core. 
 
     
     
       9. The solenoid device according to  claim 8 ,
 wherein, after the first electromagnetic coil is energized in the energization state, the second electromagnetic coil is energized so that the magnetic flux generated by energization to the second electromagnetic coil flows in the second plunger, and 
 wherein, after the second electromagnetic coil is energized, energization to the first electromagnetic coil is terminated so that only attraction of the first plunger is cancelled under a condition that the second plunger and the third plunger are attracted by the magnetic flux of the second electromagnetic coil. 
 
     
     
       10. The solenoid device according to  claim 8 ,
 wherein, when the second electromagnetic coil is energized before the first electromagnetic coil is energized, only the third plunger is attracted toward the third fixed core. 
 
     
     
       11. The solenoid device according to  claim 8 ,
 wherein the second plunger includes: a body to be attracted toward the second fixed core; a diameter-reduced part projecting from the body to a side opposite to the second fixed core in the backward-forward movement direction of the second plunger; and a diameter-enlarged part disposed on the diameter-reduced part and having a diameter larger than the diameter-reduced part, 
 wherein the body, the diameter-reduced part and the diameter-enlarged part are made of soft magnetic material, 
 wherein the yoke includes a first yoke part and a second yoke part separated apart from the first yoke part, 
 wherein the body slides in contact with the first yoke part, 
 wherein the third plunger slides in contact with the second yoke part, 
 wherein, when the second plunger is attracted toward the second fixed core, the diameter-enlarged part comes close to the second yoke part and a gap between the second plunger and the second yoke part is reduced, and 
 wherein, when the second plunger is not attracted toward the second fixed core, the diameter-enlarged part is disposed apart from the second yoke part and the diameter-reduced part moves close to the second yoke part, so that the gap between the second plunger and the second yoke part becomes wider than a case where the second plunger is attracted toward the second fixed core. 
 
     
     
       12. The solenoid device according to  claim 8 ,
 wherein the second plunger includes: a body to be attracted toward the second fixed core; and a diameter-enlarged part having a diameter larger than the body, 
 wherein the body and the diameter-enlarged part are made of soft magnetic material, 
 wherein the yoke includes a first yoke part, a second yoke part, a third yoke part, a fourth yoke part, a fifth yoke part, and a sixth yoke part, 
 wherein the body of the second plunger and the first plunger slide in contact with the first yoke part, 
 wherein the second yoke part is apart from the first yoke part, 
 wherein the third plunger slides in contact with the second yoke part, 
 wherein the third yoke part is connected to the third fixed core, 
 wherein the fourth yoke part is connected to the second fixed core and the first fixed core, 
 wherein the fifth yoke part connects between the first yoke part and the third yoke part, 
 wherein the sixth yoke part connects between the second yoke part and the third yoke part, 
 the solenoid device further comprising: 
 a notch for suppressing a flow of the magnetic flux between the third yoke part and the fourth yoke part, 
 wherein the notch is disposed between the third yoke part and the fourth yoke part, 
 wherein, when the second plunger is attracted toward the second fixed core, the diameter-enlarged part comes close to the second yoke part so that a shortest distance between the second plunger and the second yoke part is reduced, and 
 wherein, when the second plunger is not attracted toward the second fixed core, the diameter-enlarged part is disposed apart from the second yoke part, and the shortest distance between the second plunger and the second yoke part becomes longer than a case where the second plunger is attracted toward the second fixed core. 
 
     
     
       13. The solenoid device according to  claim 8 ,
 wherein a center axis of one of the first plunger, the second plunger and the third plunger turns to a direction, which is different from center axes of other two of the first plunger, the second plunger and the third plunger. 
 
     
     
       14. The solenoid device according to  claim 8 ,
 wherein at least one of the first plunger, the second plunger and the third plunger includes a flange, which protrudes from a body of the at least one of the first plunger, the second plunger and the third plunger in a radial direction of the at least one of the first plunger, the second plunger and the third plunger, and 
 wherein the magnetic flux passes through the flange.